/*
 * TextServices / TSDotNet / TSNative
 * Marco Maria Bellocchi, Mauro Bampo
 * Copyright(c) 2013.
 * 
 * The MIT License
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 * 
 */

// MB 25/01/2013: Created

#include "stdafx.h"
#include "CharToNibbleDecoder.h"

using namespace TSNative::Filters;

CharToNibbleDecoder::CharToNibbleDecoder(const char* pDictionary) {
	_pDictionary = pDictionary;
}

inline const char* CharToNibbleDecoder::Dictionary() {
	return _pDictionary;
}

int CharToNibbleDecoder::GetInitialBufferLength(int nInputLength) {
	return nInputLength*5/2 + 2;
}

FilterState CharToNibbleDecoder::Process(const char* pInput, int inputLength, char** ppBuffer, int bufferLength, FilterState inputState) {
	FilterState outputState;
	outputState.InputIndex = inputState.InputIndex;
	char* pOutput = *ppBuffer;
	int ii = inputState.InputIndex;
	int io = inputState.OutputIndex;
	char cIn = pInput[ii];
	int nProcessed = 0;
	int currIdx = -1;
	for(; ii<inputLength && io<bufferLength; nProcessed++) {
		cIn = pInput[ii];
		if(cIn == '\0') {
			break;
		}
		currIdx = (cIn >> (4 * (nProcessed % 2))) & 0x0F;
		char cOut = Dictionary()[currIdx];
		// If not padding, write... should we check that padding is last char?
		if(cOut != Dictionary()[15]) {
			pOutput[io] = cOut;
			io++;
		}
		if((nProcessed % 2) == 1)
			// Advance input
			ii++;
	}
	if(io >= bufferLength && ii < inputLength && cIn != '\0')
		outputState.Overflow = true;
	// Add terminator
	if(io < bufferLength)
		pOutput[io++] = '\0';
	outputState.InputIndex = ii-1;
	outputState.OutputIndex = io-1;
	return outputState;
}